The use of integers in the IRIs makes it difficult to adopt and use the terminology.
I hear that it's done to avoid "meaning creep", but the unwillingness to commit to a name could cause just as much creep... for example I'm willing to buy into http://semanticscience.org/resource/experiment but that label might bind to a different integer in the future (if I understand the design correctly). That's scary and unreliable.
There's a trick where you can use the label instead of the integer, but it violates the Title Case convention. For example, http://semanticscience.org/resource/SIO_000994 can be http://semanticscience.org/resource/experiment but http://semanticscience.org/resource/Experiment 404s.

RDF version of the DisGeNET database, which is a database that integrates gene-disease associations from several public, expert, curated data sources (CTD, Uniprot, ClinVar), predictions from animal model databases, and text mining derived associations. DisGeNET-RDF is an alternative way to access the DisGeNET data and provides new opportunities for data integration, querying and integrating DisGeNET data to other external RDF datasets. The RDF version of DisGeNET has been developed in the context of the Open PHACTS project to provide disease relevant information to the knowledge base on pharmacological data.

The G protein-coupled receptors (GPCRs) ontology (http://www.bioassayontology.org/bao_gpcr) describes pharmacology, biochemistry and physiology of these important and therapeutically promising class of academic and pharmaceutical research targets. Incorporation and comparison of various small molecule screening data sets, such as those deposited in PubChem, ChEMBL, KEGG, PDSP, and/or IUPHAR databases, requires a formalized electronic organization system. In order to bridge the gap between the overflow of HTS data and the bottleneck of integrated analysis tools, herein, we provide the first comprehensive GPCR ontology. The development and utility of GPCR ontology was based on previously developed BioAssay Ontology (BAO). The GPCR ontology contains information about biochemical, pharmacological, and functional properties of individual GPCRs as well as GPCR-selective ligands inclusive of their HTS screening results and other records. This provides the first all-inclusive GPCR ontology with all available data to model the relationship between the GPCR binding sites and their physiologic and pharmacologic role in physiology via small molecule chemical structures. We developed this system using emerging semantic technologies, by leveraging existing and descriptive domain level ontologies.